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Re: [Detaolb-devel] [Qemu-devel] ANN: DetaolB v0.4 is released


From: Christian MICHON
Subject: Re: [Detaolb-devel] [Qemu-devel] ANN: DetaolB v0.4 is released
Date: Wed, 11 Jul 2007 15:34:17 +0200

On 7/11/07, Blue Swirl <address@hidden> wrote:
> It's entirely possibly that qemu and real sparc hardware are behaving
> differently, but I'm not seeing this bus error under qemu.  (I haven't got
> real sparc hardware, so I can only debug against qemu...)

Right. Debugging the problem I found out that in Qemu, 64-bit loads
and stores to unaligned addresses do not trigger any traps as they
should. I'll commit a fix soon. The problem is in uClibc ldso, there
is this kind of store.

Running the program on qemu-sparc reveals another problem, probably
because of these definitions in ldso/ldso/sparc/dl-sysdep.h:
/* 4096 bytes alignment */
/* ...but 8192 is required for mmap() on sparc64 kernel */
#define PAGE_ALIGN 0xffffe000
#define ADDR_ALIGN 0x1fff
#define OFFS_ALIGN 0x7fffe000

On Sparc32 the correct page alignment is still 4096. Because of these
definitions, some code apparently tries to clear a 8k page, but only
4k of memory is mapped.


I just managed a compilation of bash-3.2 using ncurses-5.6 and
uClibc-0.9.29 inside a qemu-system-sparc (native compilation,
no cross compilation).

"ldd ./bash" points naturally to libdl.so.0, libc.so.0, ld-uClibc.so.0

./bash
Segmentation fault

I do not have gdb compiled yet... I'll check soon with busybox
ash, since I recompiled uClibc with the sched_affinity patch.

--
Christian
--
http://detaolb.sourceforge.net/, a linux distribution for Qemu




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